Clean the mushrooms with a damp paper towel or cloth. Remove the stems

Place the mushrooms, gill-side down, on a foil-lined baking sheet, and brush them with the olive oil.

Place the mushrooms in the oven for 12 minutes.

Remove the pan from the oven, flip over the mushrooms, and cook for another 5-10 minutes, or until most of the liquid released by the mushrooms has evaporated.

Remove from the oven and let cool

Turn oven heat down to 350°F

While the mushroom caps are cooking, pulse the shrimp, green onions, cilantro and fish sauce in a food processor or blender 3-4 times to combine and form a paste-like mixture. When the mushroom caps have cooled, fill each cap with a rounded spoonful of the stuffing mixture and place them on a foil-lined cookie sheet.

Bake in the oven for 10 minutes. Remove from oven and drizzle sweet chili sauce on each mushroom. Serve immediately.